Depth profile of structure, strain, and composition in an annealed Al-Cu-Fe-Cr quasicrystalline film

Quasicrystalline films were formed by RF sputtering from a powder composite target onto Inconel substrates, which produces a polymorphic nanoquasicrystalline grain structure, similar to2.5 - 10 nm. Subsequent annealing at 500degreesC for 4 hours, at base pressures of below 5*10(-5) Torr, and with At flow to 5 - 10 mT, fully develops the quasicrystalline structure with decagonal phase predominating, except near the termination surface. Analysis by XPS indicated extensive oxygen incorporation and limited aluminum enrichment at the termination surface. These results are correlated with structure and strain analysis via synchrotron grazing incidence x-ray scattering (GIXS). By varying the incident angle, hence the x-ray penetration depth, the evolution of an amorphous and crystalline crystalline secondary phases at the surface of the film has been detected. Residual strain analysis shows that this second phase induces a compressive residual strain of approximate to 0.10% as measured from the displacement of the major quasicrystalline peaks in the surface layers of the film.